The present invention relates to a weft yarn measuring and storing device of a loom.
For example, Japanese Unexamined Utility Model Application Publication No. 4-97886 discloses a weft yarn measuring and storing device having a roller mechanism that feeds a weft yarn in a weft package to a storing drum for storing therein the weft yarn. The weft yarn measuring and storing device of the Publication further has a rotary drum having at one axial end thereof an annular storing portion and at the other end thereof an annular measuring portion. A pressing roller is disposed in pressure contact with the measuring portion of the rotary drum by means of a spring. The pressing roller is rotated with the rotation of the measuring portion.
The weft yarn fed from the weft yarn package is pinched between the rotating pressing roller and the measuring portion of the rotating rotary drum and further fed out toward the storing portion. The weft yarn is wound around the storing portion by the action of air flow circling around the storing portion. At a start of a weft insertion, the weft yarn wound around the storing portion is pulled out through the weft insertion nozzle to be inserted. When the weft yarn on the storing portion is all pulled out, the weft yarn that is fed out through the rotation of the pressing roller and the measuring portion is directly used for weft insertion.
In the weft yarn measuring and storing device disclosed in the above Publication, when the drum is rotated at a high speed with an increase of the loom operating speed, a force acting against the pulling force of the spring is generated to thereby cause the pressing roller to be separated from the measuring portion of the drum. The function of feeding the weft yarn is stopped while the pressing roller is separated, which causes measurement of a weft yarn that is shorter than the required length. Such measurement of a weft yarn of an insufficient length by the weft yarn measuring and storing portion is a major factor of mispicking.
In order to prevent the separation of the pressing roller, it has been contemplated to increase the force of the spring by which the pressing roller is pressed to be contacted against the measuring portion of the drum. Generally, the surface of the pressing roller is clad with rubber for enhancing the weft yarn feeding performance. However, the increase of the force of the spring for increasing the pressing force of the pressing roller against the measuring portion significantly shortens the service life of the rubber covering the pressing roller, resulting in frequent replacements of the pressing rollers. Since the pressing roller that is integrally formed with the rubber covering is expensive, it is strongly desired that the frequency of replacement of the pressing rollers should be reduced.
In view of the circumstances above, the present invention is directed to providing a weft yarn measuring and storing device of a loom that prevents the separation of a feed roller of the weft yarn measuring and storing device that occurs during operation of the loom without increasing the frequency of replacement of the feed rollers.